The purpose of this research study is to find out if a surgical procedure called "decompression coring," when done in the early stages of avascular necrosis (AVN), is more effective in slowing the progression of AVN than is non-weight bearing with crutches and no surgery. Decompression coring is major surgery, but involves less risk than total hip replacement (THP). It is important to find out whether or not hip coring can benefit patients with AVN and reduce the need for THR. It is not known whether decompression coring is more effective than conservative treatment with crutch-walking alone to avoid weight bearing on the affected hip.